Variable magnification optical system, optical device, and method for manufacturing variable magnification optical system

Abstract

A variable magnification optical system includes, in order from an object side, a first lens group having positive refractive power; a second lens group having negative refractive power; and a third lens group having positive refractive power; upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group and a distance between the second lens group and the third lens group being varied. The variable magnification optical system further includes a V lens group GV having negative refractive power and being moved to have a component in a direction perpendicular to the optical axis, and an F lens group GF having positive refractive power and being moved along the optical axis upon focusing from an infinitely distant object to a close object, the V lens group GV being disposed on the more object side than the F lens group GF. Thereby, it is possible to provide the compact variable magnification optical system with a high zoom ratio and high performance, an optical apparatus therewith and a method for manufacturing the variable magnification optical system.

What is claimed is: 
     
       1. A variable magnification optical system comprising, in order from an object side, a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having negative refractive power; and a fifth lens group having positive refractive power;
 upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group being varied; the first lens group being moved along an optical axis; and the position of the fifth lens group being fixed; and 
 the following conditional expression being satisfied: 
 
       
         
           
             
               0.170 
               < 
               
                 
                   
                     ( 
                     
                       
                         - 
                         f 
                       
                       ⁢ 
                       4 
                     
                     ) 
                   
                   / 
                   f 
                 
                 ⁢ 
                 5 
               
               < 
               0.400 
             
           
         
         where f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group. 
       
     
     
       2. The variable magnification optical system according to  claim 1 , wherein, upon zooming from the wide-angle end state to the telephoto end state, the third lens group is moved to the object side. 
     
     
       3. The variable magnification optical system according to  claim 1 , wherein, upon zooming from the wide-angle end state to the telephoto end state, the fourth lens group is moved to the object side. 
     
     
       4. The variable magnification optical system according to  claim 1 , wherein, upon zooming from the wide-angle end state to the telephoto end state, the first lens group is moved to the object side. 
     
     
       5. The variable magnification optical system according to  claim 1 , wherein, upon zooming from the wide-angle end state to the telephoto end state, the second lens group is moved along the optical axis. 
     
     
       6. The variable magnification optical system according to  claim 1 , wherein the following conditional expression is satisfied: 
       
         
           
             
               
                 5. 
                 ⁢ 
                 5 
                 ⁢ 
                 0 
                 ⁢ 
                 0 
               
               < 
               
                 f1 
                 / 
                 fw 
               
               < 
               9.000 
             
           
         
         where fw denotes a focal length of the variable magnification optical system in the wide-angle end state, and f1 denotes a focal length of the first lens group. 
       
     
     
       7. The variable magnification optical system according to  claim 1 , wherein the following conditional expression is satisfied: 
       
         
           
             
               
                 10. 
                 ⁢ 
                 5 
                 ⁢ 
                 0 
                 ⁢ 
                 0 
               
               < 
               
                 f5 
                 / 
                 fw 
               
               < 
               
                 3 
                 ⁢ 
                 
                   0 
                   . 
                   0 
                 
                 ⁢ 
                 0 
                 ⁢ 
                 0 
               
             
           
         
         where fw denotes the focal length of the variable magnification optical system in the wide-angle end state, and f5 denotes the focal length of the fifth lens group. 
       
     
     
       8. The variable magnification optical system according to  claim 1 , wherein the following conditional expression is satisfied: 
       
         
           
             
               0.150 
               < 
               
                 ( 
                 
                   
                     
                       d 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       4 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       t 
                     
                     - 
                     
                       d 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       4 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       
                         w 
                         / 
                         ft 
                       
                     
                   
                   < 
                   0.350 
                 
               
             
           
         
         where ft denotes a focal length of the variable magnification optical system in the telephoto end state, d4w denotes a vertex distance between a most image side lens surface of the fourth lens group and a most object side lens surface of the fifth lens group in the wide-angle end state, and d4t denotes a vertex distance between a most image side lens surface of the fourth lens group and a most object side lens surface of the fifth lens group in the telephoto end state. 
       
     
     
       9. An optical apparatus equipped with the variable magnification optical system according to  claim 1 . 
     
     
       10. A method for manufacturing a variable magnification optical system, comprising:
 arranging, in order from the object side: a first lens group having positive refractive power; a second lens group having negative refractive power; a third lens group having positive refractive power; a fourth lens group having negative refractive power and a fifth lens group having positive refractive power; 
 constructing the fourth lens group and the fifth lens group to satisfy the following conditional expression:
   0.170<(− f 4)/ f 5<0.400
 
 
 where f4 denotes a focal length of the fourth lens group, and f5 denotes a focal length of the fifth lens group; and 
 constructing such that, upon zooming from a wide-angle end state to a tele photo end state, a distance between the first lens group and the second lens group, a distance between the second lens group and the third lens group, a distance between the third lens group and the fourth lens group and a distance between the fourth lens group and the fifth lens group are varied, the first lens group is moved along optical axis, and the position of the fifth lens group is fixed. 
 
     
     
       11. The variable magnification optical system according to  claim 1 , wherein the third lens group includes a V lens group movable so as to have a movement component in a direction perpendicular to the optical axis. 
     
     
       12. The variable magnification optical system according to  claim 11 , wherein an F lens group is disposed on an image side of the V lens group, and the F lens group is moved along the optical axis upon focusing from an infinitely distant object to a close object. 
     
     
       13. The variable magnification optical system according to  claim 1 , wherein the fifth lens group includes an aspherical lens.